Methods and systems for magnetically suspending tissue structures

ABSTRACT

A system for magnetically suspending tissue includes a grasper placement tool, a tissue grasper, a magnetic coupling element, and a tether which secures the magnetic coupling element to the tissue grasper. The grasper placement tool is used to simultaneously introduce both the tissue grasper and the magnetic coupling element to a body cavity. The grasper then releases the magnetic coupling element and engages a target tissue structure. The tissue grasper is then detached from the placement tool and a conventional laparoscopic or other grasper is used to engage the magnetic coupling element to an external magnet.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/384,098 (Attorney Docket No. 43823-703.302), filed Dec. 19, 2016, nowU.S. Pat. No. ______, which is a continuation of U.S. patent applicationSer. No. 14/030,581 (Attorney Docket No. 43823-703.201), filed Sep. 18,2013, now U.S. Pat. No. 9,554,818, which claims the benefit of U.S.Provisional Application No. 61/770,159 (Attorney Docket No.43823-703.101), filed on Feb. 27, 2013, the full disclosures of whichare incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates generally to medical devices and methods.More particularly, the present invention relates to methods and systemsfor magnetically suspending tissue structures during minimally invasivesurgical procedures.

A number of surgical procedures which previously required open surgeryare now performed by laparoscopy and other minimally invasiveprocedures. In laparoscopic procedures, a camera and a number of toolsare introduced into a body cavity through ports or other passages formedthrough the patient's skin. In many procedures, the abdomen isinsufflated and several ports are placed through the patient's abdominalwall. The camera is introduced through one of the ports, and theremaining ports are used for introducing tools needed to manipulateinternal tissue structures and to remove, oblate, cauterize, cut, orotherwise modify these tissue structures.

One limitation of such laparoscopic and other minimally invasiveprocedures is the limited number of ports available at any one time toaccommodate the tools required to perform the procedures. In order toreduce the number of needed ports, it has been proposed to use externalmagnets to suspend and position organs. The magnets could thus performthe role of a tissue grasper without the need to utilize one of theavailable access ports. For example, a magnetic element may beintroduced into the body cavity through a port or otherwise. Themagnetic element will be coupled to a target organ and an externalmagnet used to attract and position the magnetic element in order to inturn position the organ as needed for the procedure. Several specificsystems for magnetically suspending organs and tissue structures aredescribed in the references identified below in the Description of theBackground Art.

Although quite promising, such magnetic tissue suspending systems havetypically been cumbersome to deploy, difficult to reposition during aprocedure, and difficult to release and remove after the procedure isover. It is an object of the present invention to overcome at least someof these deficiencies.

2. Description of the Background Art

U.S. Patent Publ. Nos. 2010/0204727; 2009/0043246; 20120088965; and20120238796 and PCT Publication WO2009/019288 describe magnetic tissuesuspension systems useful in laparoscopic procedures. U.S. Pat. No.7,169,104 describes a magnetic tissue suspension system useful inendoscopic procedures. U.S. Pat. No. 7,766,810; U.S. Patent Publ.2008/0171907; and WO2008/089049 describe systems for filling an organwith a magnetic material and thereafter magnetically manipulating theorgan.

SUMMARY OF THE INVENTION

The present invention provides improved methods and systems formagnetically suspending and manipulating tissue structures duringlaparoscopy and other minimally invasive surgical procedures. Themethods and systems provide a simplified and efficient protocol forintroducing a tissue grasper attached to a magnetic element into a bodycavity through a laparoscopic port or other tissue passage. The tissuegrasper, magnetic element, and an adjustable tether connecting themtogether, are introduced simultaneously through the laparoscopic port orother tissue passage using a single shaft. After releasing the magneticelement from the shaft, the shaft is used to position the tissue grasperadjacent to the target tissue structure. The tissue grasper is thenopened, placed over the tissue structure, and closed to firmly grasp thetissue structure. The tissue grasper is then released from the singleshaft and the shaft removed from the body cavity. A conventional orother laparoscopic grasper is then introduced into the body cavity tograsp the magnetic element and position the magnetic element adjacent toan external magnet which attracts the magnetic element and allowspositioning the element by moving the external magnet over the patient'sskin. The laparoscopic grasper can also be used to tighten or cinch thetether by pulling on the tether which locks in place after appropriatetensioning.

A particular object of the present invention is to provide variablecontrol of the magnetic field which is created between the magneticcoupling element within the body cavity and the external suspensionmagnet present over the patient's skin. While the use of fixed magnetsand/or magnetic materials which are not themselves magnets comes withinthe scope of the present invention, it will be preferable if at leastone of the magnetic coupling element and the external suspension magnetis configured to provide an adjustable magnetic field. The most commonmagnets having adjustable field strength are electromagnets, whichtypically comprise a wound helical coil of wire, usually having an ironcore. When current flows through the helical coil, the iron core acts asa magnet, where the strength and polarity of the magnetic field createdare adjustable by changing the magnitude of and/or the direction ofcurrent flow through the wire. A variety of conventional circuits areavailable for coupling to an electromagnet to provide a variable,adjustable magnetic field.

While usually at least one of the magnetic coupling element and theexternal suspension magnet will have an adjustable magnetic field, theother magnetic element may be a permanent magnet or a temporary magnet.Permanent magnets are those which retain a generally fixed level ofmagnetism over time and which are typically made of permanentlymagnetizable materials, such as neodymium-iron-boron alloys,samarium-cobalt alloys, alnico alloys, as well as ceramic and ferritematerials. Temporary magnets are typically made from iron and otherferrite materials.

While using an electromagnet or other magnet having an adjustable fieldas the external suspension magnet will be most common, it will also bepossible to use an electromagnet or other adjustable field magnet as themagnetic coupling element within the body cavity. In some cases, it willbe desirable to form both the external suspension magnet and themagnetic coupling element as electromagnets or other adjustable fieldstrength magnets. It will be appreciated that by having both theexternal suspension magnet and the internal magnetic coupling element becapable of providing an adjustable magnetic field, the magnetic tractionbetween these magnetic elements can be adjustable over a wide range offield strengths. The ability to adjust the field strength is desirablefor many reasons. For example, the strength may be adjusted when it isdesirable to move the external suspension magnet over the patient's bodysurface in order to pull or drag the internally located magneticcoupling element. It will also be desirable to be able to adjust themagnetic field strength at different portions of the surgical procedure.A strong magnetic field may be necessary at times that significanttension is being placed on the tether. At other times, however, it maybe desirable to reduce the magnetic strength between the magneticcoupling element and the external suspension magnet, for example inorder to lessen the compressive force being applied to the tissue inorder to reduce the inhibition of blood circulation over extended timeperiods. The electromagnet will usually include a controller unit, andthe controller unit will usually be adjustable or programmable for oneor more purposes. For example, software may be provided to determine orcalculate the optimal magnetic force to accommodate an abdominalthickness, tool size, supporting force, or the like, and to calculatethe desired holding force and the electrical power needed to generatethe desired force.

In a first aspect of the present invention, a tissue suspension systemcomprises a grasper placement tool having a shaft, a tissue grasper, amagnetic coupling element, and a tether securing the magnetic couplingelement to the tissue grasper. The tissue grasper is detachably securedto a distal end of the shaft, allowing the tissue grasper to be releasedonce it has been secured to a target tissue structure. Such a releasemechanism eliminates the need to provide a separate tool to remove andplace the tissue grasper as required by several of the proposed system.

In a preferred aspect, the grasper placement tool has a rigid narrowshaft configured for laparoscopic introduction into a patient'sinsufflated abdomen. Typically, the shaft will have a diameter intendedfor insertion through a convention laparoscopic port, e.g. having adiameter of 5 mm, 10 mm, or 12 mm. The tissue grasper may be secured tothe shaft of the grasper placement tool by any suitable mechanicalattachment mechanism, typically being a bayonet attachment which can bereleased via a mechanism located at a proximal end of the shaft. Thetissue grasper typically includes a pair of clamping jaws which can beopened and closed from the proximal end of the shaft. The tissue grasperis specifically configured to be closed over the tissue structure whilethe tissue grasper remains attached to the shaft. The tissue grasper isfurther preferably configured to remain closed over the tissue evenafter being detached from the shaft.

In specific embodiments of the present invention, the jaws of the tissuegrasper will be attached to a rod which can be moved in order to openand close the jaws. Typically, the tissue grasper placement toolincludes a driver which engages the rod of the tissue grasper allowingthe rod to be reciprocated in order to open and close the jaws while thetissue grasper remains on the shaft.

In further specific embodiments, the magnetic coupling element will beconfigured so that it can be carried by the jaws when the grasperplacement tool is being introduced into the body cavity. In suchconfiguration, the magnetic element, the tissue grasper, and the shaftof the tissue grasper placement tool will preferably be coaxiallyaligned in order to minimize the profile and allow the assembly to beintroduced through a laparoscopic or other port simultaneously in asingle motion. That is, the tissue grasper will have an axis which isaligned with an axis of the shaft and usually with an axis of themagnetic element. This allows the shaft, tissue grasper, and magneticelement to be inserted together in tandem through the laparoscopic portof other access passage.

The length of tether between the tissue grasper and the magnetic elementis preferably adjustable. For example, the tether may be configured tobe pulled through the magnetic coupling element and to be selectivelylocked once a proper tension on the tissue structure has been achieved.A variety of suitable locking mechanisms may be provided on the magneticelement, including mechanically actuable locking mechanisms andmagnetically actuable locking mechanisms. In some embodiments, as asafety measure, the locking mechanism can be configured to allow thetether to slip when excessive tension is applied.

The assembly of the tissue grasper placement tool, magnetic element, andtether, as just described, will usually be combined in a system thatfurther includes the external magnet and optionally a frame, arm orother support structure for holding the external magnet in place duringa procedure. Such support structures will typically be configured to besecured to a table and they may optionally include a shape lockmechanism for facilitating repositioning.

In a second aspect, the present invention comprises a method forsupporting an internal tissue structure using an external magnet. Ashaft is introduced through a percutaneous passage, such as alaparoscopic port, into a body cavity of a patient, such as aninsufflated abdomen. A distal end of the shaft carries a tissue grasperand a magnetic coupling element. The tissue grasper is secured to themagnetic coupling element by a tether. The magnetic coupling element isreleased from the shaft within the cavity while maintaining connected tothe grasper by the tether. The tissue grasper is then secured over thetissue structure while the grasper remains on the shaft. Usually, adriver or other mechanism in the shaft is used to lock the grasper inthe required gripped position. The tissue grasper is then released fromthe shaft after having been secured over the tissue structure. Theexternal magnet is then positioned over the patient's skin to attractand hold the magnetic coupling element in place. The tether is thencinched to position the tissue structure as desired.

The shaft, tissue grasper, and magnetic coupling element are usuallyaligned in tandem as they are introduced through the percutaneouspassage. Such an aligned configuration simplifies the introduction ofthese three system components, significantly reducing the complexity ofthe procedure. Typically, the magnetic coupling element is carried bythe tissue grasper while being introduced through the port of othertissue passage, and the magnetic coupling element can be released bysimply opening the tissue grasper.

The tissue grasper typically comprises opposed jaws, and securing thetissue grasper over the tissue comprises closing the jaws over thetissue where the jaws remain closed after the tissue grasper has beenreleased from the shaft. In specific embodiments, closing the jaws overthe tissue structure comprises actuating a driver in the shaft to causethe jaws to close where the jaws remain closed after such actuationstops.

Releasing the tissue grasper from the shaft typically comprisesactuating a coupling mechanism, such as a bayonet connector, on theshaft, to release the tissue grasper. The methods may further comprisepositioning the external magnet using a supporting structure, such assupport arm attached to the patient bed or operating table. Cinching thetether may comprise grasping the tether and pulling the tether through alock on at least one of the magnetic coupling element in the tissuegrasper. The methods may further comprise releasing the tissue grasperfrom the tissue structure after the procedure has been completed.

INCORPORATION BY REFERENCE

All publications, patents, and patent applications mentioned in thisspecification are herein incorporated by reference to the same extent asif each individual publication, patent, or patent application wasspecifically and individually indicated to be incorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIG. 1 illustrates the grasper placement tool connected to a tissuegrasper and a magnetic element in accordance with the principles of thepresent invention.

FIGS. 2A and 2B are detailed end views of the grasper placement tool ofFIG. 1 shown with the tissue grasper holding the magnetic element (FIG.2A) and with the tissue grasper open (FIG. 2B).

FIG. 3 is a cross-sectional view of the grasper placement tool of FIG. 1shown without the tissue grasper.

FIG. 4A is a detailed, end view of the grasper placement tool shown witha bayonet connector holding the tissue grasper in place.

FIG. 4B is a detailed, end view of the grasper placement tool shown withthe jaws of the tissue grasper open.

FIG. 4C is a detailed, end view of the grasper placement tool of thepresent invention shown with the tissue grasper detached from thebayonet connector.

FIGS. 5A-5F illustrate a first exemplary embodiment of a tissue grasperconstructed in accordance with the principles of the present invention.

FIGS. 5G-5I illustrate a second exemplary embodiment of a tissue grasperconstructed in accordance with the principles of the present invention.

FIGS. 6A and 6B illustrate a third exemplary embodiment of a tissuegrasper constructed in accordance with the principles of the presentinvention.

FIGS. 7A-7C illustrate a fourth embodiment of a tissue grasperconstructed in accordance with the principles of the present invention.

FIGS. 8A and 8B illustrate a first embodiment of an exemplary magneticelement constructed in accordance with the principles of the presentinvention.

FIGS. 9A and 9B illustrate a second exemplary embodiment of a magneticelement constructed in accordance with the principles of the presentinvention.

FIGS. 10A and 10B illustrate a third exemplary embodiment of a magneticelement constructed in accordance with the principles of the presentinvention.

FIG. 10C illustrates an electromagnetic element useful in the magneticelement embodiments of the present invention.

FIGS. 11A-11I illustrate the grasper placement tool of the presentinvention used for positioning a tissue grasper and magneticallysuspending it in accordance with an exemplary embodiment of the methodsof the present invention.

FIGS. 12A and 12B illustrate an exemplary external magnet constructed inaccordance with the principles of the present invention.

FIGS. 13A and 13B illustrate the external magnet being supported by ashape-lock arm in accordance with the principles of the presentinvention.

FIGS. 14A-14D illustrate a fourth exemplary embodiment of a tissuegrasper constructed in accordance with the principles of the presentinvention.

FIGS. 15A-15D illustrate a fifth exemplary embodiment of a tissuegrasper constructed in accordance with the principles of the presentinvention.

FIGS. 16A-16C illustrate a sixth exemplary embodiment of a tissuegrasper constructed in accordance with the principles of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, a tissue grasper placement tool 10 includes a shaft12 which carries a tissue grasper 14 at its distal end. A magneticelement 16 is secured to the tissue grasper 14 by a tether 18. A handle20 at the proximal end of shaft 12 includes a trigger 22 which is usedfor opening and closing the oppose jaws 34 and 36 and also for detachingthe tissue grasper 14 from the shaft 12, as will be described in moredetail below. A detachment sleeve 23 on shaft 12 is also provided todetach the tissue grasper 14, and a rotatable knob 24 is provided at theproximal end of a driver 28 (FIGS. 2A, 2B and 3) and is used to locktheopposed jaws 34 and 36 of the tissue grasper 14 in place in any desiredposition, as will also be described in more detail below.

Referring now to FIGS. 2A and 2B, the tissue grasper 14 will preferablyhold the magnetic element 16 between the opposed jaws 34 and 36, asshown in FIG. 2A, while the tool end is being introduced into a targetbody cavity through a laparoscopic port or other tissue passage. Once inplace, the jaws 34 and 36 may opened, as shown in FIG. 2B, to releasethe magnetic element 16. In the open configuration of FIG. 2B, the jaws34 and 36 of tissue grasper 14 will also be in position to engage and betightened over a target tissue structure, as will be described in moredetail below.

Referring now to FIG. 3, a bayonet connector 26 used for detachablysecuring the tissue grasper 14 in the position shown in FIG. 1. Thebayonet connector may be of generally conventional construction,including one or a pair of detents 27 which are received in opposedapertures 32 (FIG. 4A) in a shank region of the tissue grasper 14. Theshaft 12 is axially split into a pair of opposed prongs 30 which may besqueezed together in order to release the detent pins 27 when it isdesired to detach the tissue grasper 14 from the shaft. The grasperrelease mechanism 23 allows the user to close the prongs and the trigger22 can be used to advance the driver 28 to push the grasper off of thebayonet connector. As shown in FIG. 3, the trigger 22 may be pulled (asshown in broken line) to advance a distal end 40 of the driver 28 (asalso shown in broken line).

Referring now to FIG. 4B, the rotatable knob 24 may be used to rotatedriver 28 (as shown by an arrow) in order to lock the opposed jaws 34and 36, as will be described in greater detail below.

FIG. 4C illustrates the tissue grasper 14 after the jaws have beenclosed and the grasper released from the bayonet connector 26.

Referring now to FIGS. 5A-5F, a first exemplary tissue grasper 114 willbe described. The tissue grasper 114 comprises an upper jaw 134pivotally attached to a lower jaw 136 and having a shank region 152 at aproximal end thereof. Although not illustrated in FIGS. 5A-5F, thebayonet connector 26 of the shaft 30 of the grasper placement tool 10will be received within the open end of the shank and will engageapertures (as described previously for detachably securing the tissuegrasper 114). The distal end 40 of the driver 28 will be configured toengage a proximal end (to the right in FIG. 5A) of a piston 150 with athreaded proximal end 154. The threaded end 154 is rotatably attached toa follower 151 secured to a link 156. In this way, the driver 28 can beused to rotate the piston between a locked configuration, as shown inFIG. 5A, where the threads on the piston engage mating threads on aninner surface of the shank 152, and an unlocked configuration as shownin FIG. 5C, where the piston has been rotated 180 degrees so that thethreads no longer engage each other. In the unlocked configuration ofFIGS. 5C and 5D, the driver 28 may be used to advance the pistondistally to close the upper jaw 134, as shown in FIG. 5E. The piston 150may then be rotated back to the position of FIG. 5A and FIG. 5B in orderto lock the jaw closed if desired. Otherwise, a spring 160 may beconfigured to self-open the jaws when the piston is free to translateand no force is applied to piston by the driver 28. Optionally, aportion 162 of the shank 152 may be pivotally attached so that theportion may be opened to disengage the piston whenever desired, allowingthe jaws to open.

In variations of the grasper 114 of FIGS. 5A-5F, the shank 152 may bereplaced by a cylinder with a full internal thread. The follower 151 andthe threaded end 154 of the piston 150 remain rotatably coupled, and ahex or other driver can be temporarily engaged with the shank 152 andpiston 150 to rotate the threaded end 154 to translate the pistondistally and proximally within the shank to open and close the jaws 134and 136. When the piston 150 is fully distally advanced against thefollower, the jaws will remain locked until the driver is re-engaged todrive the piston 150 proximally to release the jaws.

Referring now to FIGS. 5G-5I, a second exemplary tissue grasper 164 willbe described. The tissue grasper 164 comprises an upper jaw 166pivotally attached to a lower jaw 168 and having a shank region 170 at aproximal end thereof. The shank region 170 is detachably received in anopen end of the shaft 12 of the previously illustrated tissue grasperplacement tool 10. A distal end 172 of a hex driver shaft 174 isconfigured to pass through a complementary hexagonal axial passagethrough a threaded piston 176 having a protruding distal end 178. Afollower 180 is pivotally attached to one end of a link 182 which ispivotally attached at its other end to the upper jaw 166. In this way,the hex driver 174 can be passed through the passage in the follower 180to engage a proximal end of the follower to close the upper jaw 166 asshown in FIG. 5H. Once the jaws have been closed over a target tissue T,the hex driver 174 can be rotated to drive the threaded piston 176forward to lock the jaws over the tissue. As with earlier embodiments, aspring 184 is provided to hold the jaws 166 and 168 open, as shown inFIG. 5G, when the follower 180 is proximally retracted. When it isdesired to release the jaws, the hex driver 174 and shaft 12 may bere-engaged with the shank 170 and the hex driver used to rotate thethreaded piston 176 to release the force against the follower 174,allowing the spring 184 to open the jaws.

Referring now to FIGS. 6A and 6B, an alternative tissue grasper 214 isillustrated. A piston 350 is attached through a link 356, and theopening/closing mechanism is similar to that described relative to FIGS.5A-5F. The piston 350, however, is not rotatable and the only means forlocking and unlocking the axial translation of the piston is a pivotingwall 362. Thus, the piston 350 is locked as shown in FIG. 6A and isunlocked as shown in FIG. 6B.

A second alternatively designed tissue grasper 314 is illustrated inFIGS. 7A-7C. Piston 350 is free to axially translate in either aproximal or distal direction within shank 352. The upper jaw 334 islocked relative to the lower jaw 336 by a curved ratchet strip 370 whichcan be opened as shown in FIG. 7B or closed as shown in FIG. 7C in orderto permit or prevent opening and closing of the jaws.

Referring now to FIGS. 8A and 8B, a first exemplary embodiment of amagnetic coupling element 416 is illustrated. The tether 18 passes at a90 degree angle from one corner of the magnetic element to an opposedcorner. A magnetic shuttle 450 can be moved from an open configuration,as shown in FIG. 8A, where the tether 18 is free to move through themagnetic element 416 to a closed configuration, as shown in FIG. 8B,where the tether 18 is locked relative to the magnetic element. Themagnetic shuttle 450 may be actuated, for example, when the magneticelement 416 is being held by the external magnet which will draw themagnetic shuttle 450 into the locked configuration as shown in FIG. 8B.This configuration is particularly convenient since no separate actionis needed to lock and unlock the tether. By properly orienting surfacefeatures 452, the tether 18 may be drawn in a cinching or tighteningdirection even when the shuttle is closed, but prevented from moving inthe opposite direction since the features 452 will cut or bite into thetether if it moves in the opposite direction.

Referring now to FIGS. 9A and 9B, an alternative magnetic element 516 isillustrated where tether 18 passes through an open passage 550. Once thetether is sufficiently tight, a locking element 560 can be moved againstthe body of the magnetic element 516, shown in FIG. 9B in order toprevent the tether 18 from being pulled out of the passage 550. Thelocking element 560 can be a conventional spring lock with a button 562available to release the lock.

Referring now to FIGS. 10A and 10B, a second alternative magneticelement 616 is illustrated. The tether has a ratcheted section 618 whichtravels past a pivoted element 620. The pivotable element 620 carries atooth 622 which engages the ratchets 618 to prevent the tether frombeing drawn out of the magnetic element. The tether, however, may betightened as the ratchet will travel over the tooth 622 in thatdirection only. A torsion or other spring element (not illustrated) isusually provided to urge the pivotable element 620 in a clockwiserotational direction against the ratcheted section 618 of the tether, asviewed in FIGS. 10A and 10B.

In all embodiments described thus far, the magnetic element may comprisean electromagnet as illustrated in FIG. 10C. An electromagnetic element700 may comprise a wire coil 702 wound over a coil 704 mounted within ahousing 706. Current is typically provided by an external power supply708 connected to the electromagnetic element by a conductor cable 710 orin some cases by a radiofrequency link. The power supply will includeconventional circuitry to allow the magnetic field strength to beadjusted by the user, typically using a knob 712 or other conventionmanual controller connected to the power supply by a second cable 714.As described elsewhere herein, the ability to adjust the magnetic fieldstrength of both the external magnet and the internal magnetic elementaffords a great deal of flexibility to the user.

Referring now to FIGS. 11A-11I, a method for magnetically suspending atissue structure in a body cavity in accordance with the principles ofthe present invention will be described. The description will be madewith respect to a tissue structure TS in an insufflated abdominal cavityA in a laparoscopic procedure, but the principles of the presentinvention will apply to other endoscopic and minimally invasiveprocedures and other body cavities as well. For ease of illustration,the presence of laparoscopic ports has not been shown, and in fact thetools of the present invention could be used without laparoscopic portsin some instances. Usually, however, the procedures would employ one ormore conventional laparoscopic ports for providing tool access.

As shown in FIG. 11A, the grasper replacement tool 10 is introduced intothe abdominal cavity A with the magnetic element 16 carried in thetissue grasper 14 which in turn is attached to the distal end of theshaft 12. By having these components axially aligned, the profile of thetool is minimized and the simultaneous introduction of all components isfacilitated.

Once in the cavity, the jaws of the tissue grasper 14 (e.g. jaws 34 and36 in FIG. 1) will be slightly opened to release the magnetic element16, as shown in FIG. 11B. Any of the release mechanisms described abovecould be employed. The tissue grasper 14 is then moved to engage thetissue structure TS, and the jaws of the tissue grasper are tightenedover the tissue structure, as shown in FIG. 11C, thus providing a firmgrasp on the tissue structure.

The tissue grasper 14 is then detached from the shaft 12 of the grasperplacement tool 10, as shown in FIG. 11D. Any of the detachmentmechanisms described above could be utilized. The grasper placement tool10 is no longer used in this procedure for suspending the tissuestructure, but it could be used for removing the tissue grasper 14 byperforming the steps that are now being described in an opposite order.

Referring now to FIG. 11E, a conventional laparoscopic grasper LG isnext introduced into the abdominal cavity, optionally through the sameport or tissue passage through which the grasper placement tool 10 hasbeen passed. The jaws of the grasper LG are then used to grasp themagnetic coupling element 16, as shown in FIG. 11F. The magneticcoupling element 16 is next raised to the vicinity of an external magnet80 which has been placed on the outer surface of the patient's abdominalwall AW, as shown in FIG. 11G. The strength of the magnetic fieldapplied by the external magnet 80 may optionally be increased at thispoint in order to hold the coupling element 16 firmly as the tether 18is cinched, as shown in FIG. 11H. The tether 18 may be cinched by usingthe jaws of grasper LG to grasp the free end of the tether and pull onsaid free end in order to tension the portion of tether 18 between thetissue grasper 14 and magnetic element 16, as shown in FIG. 11H. Oncethe proper tension has been applied, as shown in FIG. 11I, the grasperLG can be released from the magnetic coupling element 16, and thephysician is ready to continue with other portions of the procedure.

An exemplary external magnet 80 is illustrated in FIGS. 12A and 12B. Theexternal magnet 80 preferably includes a side coupler 82 which permitsattachment to a support arm, as described hereinafter. An electromagnetis formed by wrapping a solenoid or coil wire 84 over a magnetic core 86in a conventional manner. Magnetic field controller 88 is provided andconnected to an electrical cord 90 to provide power. Both a fieldstrength adjustment knob 92 and a lock button 94 may be provided forunlocking the support frame 180. An unlock button 96 may be provided forreleasing the magnetic element 16. Of particular use, the magnetic fieldstrength may be adjusted using the knob 92 to an appropriate level tofacilitate movement of the external magnet 80 over the patient's skin inwhen it is desired to move the magnetic element 16 within the bodycavity in order to manipulate the tissue structure TS. Circuits forsmoothly adjusting the strength of an electromagnet from zero to maximumare well known in the art. See, for example, the circuit descriptionsavailable at http://homemadecircuitsandschematics.blogspot.com/.

Usually, the external magnet 80 will be held in place using a supportframe 180, as shown in FIGS. 13A and 13B. The support frame 180 mayinclude a stand 182 which may be secured to the side of a bed or tableT. An arm 184, such as a shape lock mechanism, may be attached to anelectronic lock 186 at the top of the stand 182. The electronic lock maybe in communication with the lok and unlock buttons 94 and 96 on theexternal magnet 80, allowing the user to lock and unlock the arm whilestill holding the magnet. In this way, the external magnet 80 may bemanually positioned over the patient P, and after the desired positionis reached, the external magnet may be locked in place until it isdesired to further move the magnet and the coupled tissue structure.

Referring now to FIGS. 14A-14D, a fourth exemplary tissue grasper 200will be described. The tissue grasper 200 comprises an upper jaw 202 topivotally attach to a lower jaw 204 and having a shank region 206 at aproximal end thereof. A grasper placement tool assembly 208 comprises aninner tubular member 210, an outer tubular member 212, and areciprocating pusher 214. A retaining ring 216 is carried near a distalend of the outer tubular member and is adapted to be pushed forwardlyover ratcheting surfaces 218 on the top and bottom of the upper jaw 202and lower jaw 204, respectively. As shown in FIG. 14A, the upper jaw 202and lower jaw 204 are held open by a spring 222 disposed about pivotmember 220. The shank 206 is held within the open end of the innertubular member 210, and pusher 214 may be advanced in a distal directionto engage a follower 226 attached to a link 224 which is configured toclose the upper jaw 202 over the lower jaw 204, as shown in FIG. 14B.

In order to hold the closed jaws together, the outer tubular member 212may be advanced distally to push the retaining ring 216 over theratcheting surfaces 218 of the upper and lower jaws, as shown in FIG.14C. The jaws will be closed and the ratcheting ring 216 advanced afterthe tissue grasper 200 has been secured onto a desired tissue targetsite. The grasper placement tool assembly 208 may then be withdrawn fromthe closed tissue grasper 200, as shown in FIG. 14D.

Referring now to FIGS. 15A-15D, a fifth alternative exemplary tissuegrasper 230 will be described. The tissue grasper 230 includes an upperjaw 232 pivotally attached to a lower jaw 234 and having a shank region236 at its proximal end. A grasper placement tool 238 comprises atubular body having a reciprocating pusher 240 mounted therein. Theshank region 236 of the tissue grasper 230 is detachably received in anopen end of the tubular body of the grasper placement tool 238. Theupper jaw 232 is attached to scissor arm 244 and the lower jaw 234 isattached to a scissor arm 242. The scissor arms are mounted in anopening 246 formed in a distal region of the shank and attached by apivot pin 248. The scissor arms 242 and 244 are configured so thatadvancement of the pusher 240 can open the jaws as will be describedbelow.

The upper jaw 232 and lower jaw 234 are normally held in their closedposition, as shown in FIGS. 15A and 15B, by a spring element (notshown). In order to open the jaws, the pusher 40 is advanced to spreadthe interior ends of the scissor arms 242 and 244, as shown in FIG. 15C.So long as the pusher arm remains advanced, the jaws will remain open,allowing them to be placed over a tissue structure by propermanipulation of the grasper placement tool 238. When the target tissueis properly between the jaws, the pusher element 240 may be proximallyretracted, allowing the spring element to close the jaws onto thetissue. Various further locking elements may be provided, such as aretaining ring as described previously.

Referring now to FIGS. 16A-16C, a sixth exemplary tissue grasper 250will be described. The tissue grasper 250 comprises an upper jaw 252pivotally attached to a lower jaw 254 and having a shank region 256 at aproximal end thereof. The shank region 256 is carried in the open end ofa grasper placement tool 258 having a tubular body. The grasperplacement tool further includes a rotatable shaft 260 which is mountedwithin the tubular body 262. The rotatable shaft 260 is coupled to athreaded shaft 264, and a threaded follower rides over the threadedshaft so that rotation of the threaded shaft translates the followerproximally and distally. In its distal-most configuration, the follower266 causes an attached link 268 to close the upper jaw which is mountedon pivot pin 270. By rotating the rotatable shaft 260 in the oppositedirection, the threaded shaft draws the follower 266 in a proximaldirection in order to open the upper jaw 252, as best seen in FIG. 16A.One advantage of the rotation drive mechanism is that no springs arerequired and the jaws 252 and 254 will be held in place by the frictionof the threaded shaft 264 and follower 266. Another advantage of therotation mechanism is that rotatable shaft 260 can be linked and rotatedby a servo motor (not illustrated) which makes this mechanism ideal foruse in robotic surgery. This provides for a very tight grasp of tissue.The grasper placement tool 258 may be removed from the tissue grasper250 after the jaws have been closed over tissue, as shown in FIG. 16C.The jaws may then be removed by recoupling the grasper placement tool258 in order to rotate the rotatable shaft 260 in the opposite directionin order to open the jaws and release them from the tissue.

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the invention. It should be understoodthat various alternatives to the embodiments of the invention describedherein may be employed in practicing the invention. It is intended thatthe following claims define the scope of the invention and that methodsand structures within the scope of these claims and their equivalents becovered thereby.

What is claimed is:
 1. A method for manipulating an internal tissuestructure using an external magnet, said method comprising: introducinga shaft through a percutaneous passage into a body cavity of a patient,wherein a distal end of the shaft carries a tissue grasper and amagnetic coupling element secured to the tissue grasper; securing thetissue grasper over the tissue structure while the tissue grasperremains on the shaft; releasing the tissue grasper from the shaft afterthe grasper has been secured over the tissue structure, where themagnetic coupling element remains attached to the tissue grasper;positioning the external magnet over a patient's skin to create amagnetic field to attract and hold the magnetic coupling element;adjusting a strength of the magnetic field between the external magnetand the magnetic coupling element to position the tissue structure.
 2. Amethod as in claim 1, wherein the tissue grasper comprises opposed jawsand securing the tissue grasper over the tissue structure comprisesclosing the jaws over the tissue therein the jaws remain closed afterthe tissue grasper is released from the shaft
 3. A method as in claim 2,wherein releasing the magnetic coupling element comprises opening thetissue grasper.
 4. A method as in claim 1, wherein the shaft, tissuegrasper, and the magnetic coupling element are aligned in tandem as theyare introduced through the percutaneous passage.
 5. A method as in claim1, wherein the adjusting the strength of the magnetic field between theexternal magnet and the magnetic coupling element comprises adjusting amagnetic strength of the external magnet.
 6. A method as in claim 1,wherein the adjusting the strength of the magnetic field between theexternal magnet and the magnetic coupling element comprises adjusting amagnetic strength of the magnetic coupling element.
 7. A method as inclaim 1, wherein the adjusting the strength of the magnetic fieldbetween the external magnet and the magnetic coupling element comprisesadjusting both a magnetic field of the external magnet and a magneticfield of the magnetic coupling element.